When the Financial Accounting Standards Board listens to what corporations are saying and helps them-- it adjusts these standards from time to time but it does have definitions that have to be maintained.

财务会计准则委员会,听取公司的意见并协助他们...,并且适时调整标准,不过有些规则始终如一

耶鲁公开课 - 金融市场课程节选

They're rules for how a company should keep its books so that there's some regularity and standards in how accounting is done.

准则规范了公司如何记账,并建立了一套,会计规范和标准

耶鲁公开课 - 金融市场课程节选

But they're not allowed to just do it their own way; they have to do it according to standards, so the GAAP accounting is standardized.

但这代表随心所欲,必须要根据标准,国际公认会计准则就是一种标准

耶鲁公开课 - 金融市场课程节选